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Fevers may help infants resist allergies

As terrifying as they may seem at the time, small babies' fevers might make them healthier down the road.

Researchers from Henry Ford Health System in Detroit reviewed the medical records of 835 children enrolled at birth in the Childhood Allergy Study and noted any illnesses with documented fevers -- defined as a temperature of at least 101 degrees -- in their first year of life. When the children were ages 6 or 7, researchers tested about half of them for reactions to dust mites, cats, dogs, bluegrass and ragweed.

Among children who had no fevers in their first year, 50% showed allergies or skin sensitivity to at least one of the allergens. Having at least one fever dropped the percentage to 46.7%, while having two or more fevers in infancy dropped the percentage to 31.3%.

The finding adds more weight to the unproven "hygiene hypothesis," which says that kids who are exposed to dirt, bacteria and animals early in life are less prone to allergies and asthma later on, Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, said in a statement. The hypothesis could help explain the dramatic worldwide increase in asthma and allergies.

The research, which appears in the February Journal of Allergy and Clinical Immunology, was funded by the National Institute of Allergy and Infectious Diseases and the National Institute of Environmental Health Sciences.